COMPASS-CHARTS 



of the Middle Ages were not acquainted with Greek cartography, 

 and this may in a way be regarded as an advantage; for they 

 were thus obliged to invent their own mode of representation. 

 For Greek thought the chief thing was to find the best expression 

 for the system of the world and the " oecumene," to solve 

 problems such as the reduction of a spherical to a plane 

 surface by projection, etc.; while the sense of accurate detail 

 was less prominent. The Italian sailor and cartographer went 

 straight to nature, unhindered by theory, and to him it appeared 

 a matter of course to set down on the map coasts and islands 

 as accurately as possible according to the course sailed and the 

 distance, without reflecting that sea and land form a spherical 

 surface. 



The Italian sea-charts seem especially to have been 

 developed in the republics of northern Italy, Genoa and Pisa, 

 and to some extent Venice. Later the Catalans of the Balearic 

 Isles and of Spain (Barcelona and Valencia) also learned the 

 art, probably from Genoa. The charts have been justly 

 admired for their correct and detailed representation of the 

 coasts known to the Italians and the seamen of the Mediter- 

 ranean; the world had never before produced any parallel to 

 such a representation. It shows that the sailors of that time 

 were masters in the use of their compass,^ and in making up 

 their reckoning. The remarkable thing is that the first known 

 compass-charts, of the beginning of the fourteenth century, 

 were already of so perfect a form that there was little to add 

 to or improve in them in later times. It looks as though this 

 type of chart suddenly sprang forth in full perfection, like 

 Athene from the brain of Zeus, without our knowing of any 

 forerunner; it held the field with its representation of the 

 coasts of the Black Sea, the Mediterranean, and western 



1 How early the error of the compass became known is uncertain. Even if 

 it was known, it seems that at any rate no attention was paid to it at first; 

 and thus the coast-Hnes were laid down on the charts according to the 

 magnetic courses and not the true ones. Later on, a constant error was as- 

 sumed and the compass was corrected in agreement therewith; but the cor- 

 rection differed somewhat in the various tovsms where compasses were made. 



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